The problem of bamboo flowering is a key one. It take about
10 to 100 years depending on the species, before bamboo
plants flower over large areas and die. Although they regenerate
from seed within a year. Because of this it can take up
to 20 years before bamboo can support a panda population
again. This of course is after the bamboo has died.
When the bamboo in one area flowers, pandas have to move
to other areas where this has not happened. Historically,
this was easy, but as the human population expanded, more
forests have been cleared for agricultural purposes, or
for the collection of fuelwood and timber. At the same time,
more human settlements and roads have been built.
Because of this, panda migration is very difficult, leaving
pandas restricted to islands of forest. Some pandas are
still hunted for their skins. A single pelt can fetch up
to US$200,000 in Japan Poachers risk the consequences -
the death penalty. More frequently, however, pandas are
caught in snares set for other animals.